Mankind has become intensively engaged in studying the biotic mechanisms of the planet because of the increase in the number of new technologies that have pronounced but not always successfully predicted social, medicobiological, and ecological consequences. It has become necessary to associate any action that affects the environment with a forecast of its possible results. This assumes that in each specific problem area there exist ideas concerning the investigated processes, estimates of the significance of different solutions, and assumptions concerning alternatives and different development possibilities. Human experience, stimulated by a marked deterioration in the living environment, has already raised the question of determining the limits of homeostasis, i.e., of the critical environmental parameter values beyond which the existence of civilization, as presently understood, turns out to be impossible. However, it is now also evident that society will not be ready in the foreseeable future to relate in comparable terms the dangers of differing technical solutions to the kinds of activities needed to achieve the optimal relationship between social benefit and possible damage. It is therefore timely to devise some universal concept to describe the influence of the artificial living environment on the conditions for existence that will enable it to be extended to all types of technogenic activity. This essentially means that it is necessary to establish the interrelationship between the stability of complex systems and technogenic risk.Since the evolution of an artificial living environment involves the processes of transmitting matter, energy, and information, thermodynamic concepts can be used to set about analyzing it. The results obtained will then have a great generality and will not require the adoption of simplified models of the systems considered. The thermodynamic approach is valid for any systems that are sufficiently large for fluctuations of their individual microstates to be smoothed out and not too far from equilibrium to enable the nonlinearity of the processes occurring to be neglected. THEORETICAL BASIS OF THE APPROACHLet us consider a thermodynamically open system that consists of physically and chemically inhomogeneous elements which are ordered in a specific way and are specifically related. The lifetime of the elements exceeds the duration of the functioning cycle of the system. This is a general condition for any technogenic systems which contain sensible components or structures. The behavior of these slowly relaxing elements is determined by the structure of the system. By structure we mean the method of organizing the elements and the nature of the coupling between them. Real systems detect the presence of spatial and temporal structures coupled to a dynamic system. The system as a whole, and also the indeterminacy inherent in it, can be characterized by the number of possible states and by the partial probability of realizing these states that fluctuate randomly with time. The syste...

When a large population group is exposed for a long period of time to any harmful factor, as in the case of radiation, for example, from the Chernobyl accident or nuclear weapons tests, the determining factors are the irradiation dose and the response of the organism to this action (i.e. the radiobiological effect). Using the average values of the dose and the corresponding probability of the radiobiological effect, the average damage to the health for this population group (the radiation risk) can be estimated from the formula Ray = DavFav(D), where Day is the average irradiation dose for the population group under study and Fay(D) is the average probability for the appearance of a radiobiological effect for man at a dose Day.This approach (using average values) is valid, however, for the cases when the entire population group is irradiated with the same and high dose, i.e. the differences in the irradiation and effects for individuals in this group can be neglected.In most real cases, in the irradiation of large groups of the population with a small dose such an average approach makes it impossible to reveal especially serious consequences for separate representatives of the population. For this reason, it is necessary to use both the distribution of the irradiation dose in a group and the distribution over individual radiosensitivity in the population [1]. The effects of other factors -chemical, social, and so on -can be superposed on the effects from the irradiation action. Then the radiation risk R is calculated as the integrated (over all dose values) product of the probability P of exceeding some dose D by the probability distribution for the appearance of a radiobiologi-